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1import {Component} from '@angular/core';
2import { AngularFireDatabase } from 'angularfire2/database';
3
4@Component({
5    selector: 'app-root',
6    templateUrl: './app.component.html',
7    styleUrls: ['./app.component.css']
8})
9export class AppComponent {
10    courses$;
11    courseObservable;
12    authors$;
13    constructor(db: AngularFireDatabase) {
14        this.courseObservable = db.list('/courses');
15        this.courses$ = this.courseObservable.valueChanges();
16        this.authors$ = db.object('/authors/1').valueChanges();
17
18    }
19    add(course: HTMLInputElement) {
20        this.courseObservable.push(course.value);
21        course.value = '';
22    }
23}
24